Equipments for transversal perforations are used in systems for the automatic processing of documents for executing perforations that facilitate the tearing of predefined sections. The documents are derived from continuous paper forms, downstream of printers and/or high speed unwinding devices. The perforations may be arranged in different sections of the document. Moreover it is often requested to modify the lengths of these perforations.
A perforating equipment of the above mentioned kind is described in the Italian patent application TO 2010A000084 filed on 8 Feb. 2010 in the name of the applicant Tecnau S.r.l. This equipment comprises a blade support with two blades, which is actuated for the rotation by a blade servomechanism in synchronism with the form for the perforation and a blade contrast with active sections and remaining inactive sections, which is rotated by a contrast servomechanism parallel to the blade support. In condition of perforation, each active section, in synchronism with the form, provide a function of contrast for the blade. In condition of non-perforation, each inactive section is spaced away from a surface of tangency with the blade, whereby avoiding the perforation on the passage of a blade maintained in movement.
Perforation devices made in accordance with that patent application execute transversal perforations at high velocity, with limited costs and high flexibility. The distances between contiguous perforations, as defined by the users, can be close each the other or spaced away. The lengths and the positions of the perforations on the documents are determined by the lengths and the axial positions of the perforating blades on the blade support. Therefore, the choice is limited to the lengths and positions of the blades currently mounted on the respective supports.
Perforations of lengths different from the lengths allowed by the blades on board of the support can only be obtained by manually replacing the blades with other blades suitable for the lengths of the desired perforations. This override is quite simple and quick. However, it involves a temporary arrest of the equipment and then the entire system for the processing of the documents.